Damper-controlling apparatus.



No.674,63|. Patented May 2l, I90I. T. F. MAHER.

DAMPERCUNTRULLING APPARATUS.

(Application led Feb. 23, 1900,)

(No Model.)

THE BOILER W4 15H-5 uPPL Y Milf/4 UNITED STATES PATENT OFFICE.

THOMAS F. MAHER, OF BOSTON, MASSAOHUSTTS, ASSIGNOR TO JOHN A. TUPPER, OF CAMBRIDGE, AND JOI-IN R. MUIR, OF NEPONSET, MASSA- CHUSETTS.

DAM PER-CONTROLLING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 674,631, dated May 21, 1901- Application led February 23, 1900. Serial No. 61195. (No model.)

To all whom, it may concern,.-

Be it known that I, THOMAS F. MAHER, a citizen of the United States, residing at Boston, county of Suolk, and State of Massachusetts, have invented an Improvement in Damper-Controlling Apparatus, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to what I shall for convenience term a damper-regulating apparatus, and although it is represented and will hereinafter be described as a means for eifecting the action of a furnace-damper it may be employed for many other purposes.

The invention in the form thereof selected for illustration includes in its construction a plunger and its casing, a resistance medium acting against the plunger, and a pipe leading into said casing to supply thereto a duid to act in opposition to said resistance medium.

The plunger may consist of a piston, and it will be connected in some convenient manner with a damper or other controlling apparatus.

The pipe to which allusion has just been made may be for conducting steam into the plunger or piston casing and may be connected with a boiler, and the action is such that when the steam-pressure increases beyond a certain point the piston will be forced in one direction, thereby closing the damper, and as the steam-pressure decreases the resistance medium will force the piston in the opposite direction, so that by regulating the position of the damper the pressure of the boiler can be main/tained at a safety-point.

In connection with the plunger or piston casingI provide a stand-pipe adapted to contain a body of Water, and this stand-pipe may inclose a pipe by which the Water can be forced up into the plunger-casing, thereby to act as a resistance against the plunger. As a convenient means for thus forcing the water up into the casing I may employ an air-pump, which for simplicity may be connected with the stand-pipe.

The apparatus is shown in one convenient embodiment thereof in the accompanying drawings, and it is illustrated as involving a stand-pipe, as A, its top plate 3, and being surmounted by the cylinder 4, said top plate constituting the lower head of the cylinder and the said cylinder having working therein a piston or plunger 6, the rod 7 of which ex-y tends through the stuffingbox 8. A furnaceflue is shown at 9, which incloses a pivoted damper l0, these parts being of any ordinary construction.

The damper-lever 12 is united to the projecting portion of the pivot 13 of the damper, and one arm of the said damper-leyeris connected, by means of a chain 14 or other suitable connection passing over direction-pulleys l5, to the plunger 7, while the other arm of the said damper-lever carries a Weight l2', which serves as a balance-weight.

A pipe l8is tapped through the upper end of the cylinder or casing, and said pipe is connected to the boiler, so that the upper side of the piston or plunger 6 is constantly subjected to boiler-pressure. The opposite or lower side of the plunger 6 has acting against it in opposition to the boiler-pressure any suitable resistance medium, (that shown in the drawings being water,) and said resistance medium is subjected to a practically constant pressure by means hereinafter described.

The stand-pipe A is hollow, as illustrated in the drawings, and connected therewith, near the bottom thereof, is any suitable air-pump B, said pump being shown as comprising a barrel containinga piston 19, having a pistonrod 20, provided on its end with a handle 2l.

The resistance medium is contained in the vessel 30, which, as illustrated in the drawings, is an open-topped vessel, which is connected with and supported by a pipe or conduit 5, extending through the cylinder-head 3. The lower end of the pipe or conduit 5 has any suitable opening 32, by means cf which free communication is established between one end of the cylinder and .the vessel 30. The water, which in this instance is the resistance medium, is supplied to the vessel 30 in any suitable way-as, for instance, by a pipe 3l.

It will be seen from the above construction IOO that if the vessel 30 isflled with water and the pump B is manipulated to pump air into' the stand-pipe A such compressed air will operate upon the liquid in the vessel 30, thereby forcing the same up through the pipe or conduit 5 into the cylinder 4, so 'that the lower side of the plunger or piston will have acting thereon a body of water which is sub jected to the pressure in the stand-pipe A.

Any suitable gage, as 16, is connected with the stand-pipe by a pipe 17, so that the exact pressure in the stand-pipe may be readily determined.

In the operation of the device air will be pumped into the stand-pipe A until the gage 16 registers the same pressure as normal boilerpressure, and assuming that this condition of affairs exists and that the damper and plunger occupy their normal or intermediate positions it will be evident that the pressure upon each side of the piston 6 will be the same, so that the device will be in a state of equilibrium. If the boiler-pressure increases, the pressure on the top of the plunger will be greater than that acting on the pressure on the upper side of the plunger will slowly force the plunger downward to thereby close the damper, the plunger in its sistance medium, which is subjected to a con stant pressure.

It will be noticed that the area of the conduit or pipe 5 is comparatively small, and hence the action of the body of Waterin passing from the cylinder l to the vessel 30 will be retarded, such operationv compelling the plunger to move slowly, and by comparatively small, as used above and as hereinafter used in the claims, I mean that the area of the conduit or pipe 5 is much smaller than the area of the piston 6-z`. e., it is small as compared with the piston only-and in case an'apparatusembodying this invention were constructed with an extremely large piston of course the area of the conduit 5 would be correspondingly large. The partial closing of the damper, as above described, will operate to check the fire, so that the steampressure in the boiler will be reduced, and when such pressure has been reduced to its normal state the downward movement of the plunger will cease and the parts will remain in equilibrium until the boiler-pressure again increases or falls below the normal. In case it falls below normal the pressure on the lower side of the plunger will exceed that on the upper side, and consequently the plunger will be given a slow upward movement -to open the damper, such upward movement being of necessity slow by reason of the slow action of the resistance medium.

It will be seen from the above description that my invention comprises a cylinder and a piston, the piston being connected to the damper and one side ofthe piston being subjected to boiler-pressure, whereby the boilerpressure tends to close the damper, while opposed to the action of theA boiler-pressure is a resistance medium acting on the opposite side of the plunger.

lt will be understood, of course, that in practice the vessel 30 will be large enough to contain all the water that is needed to ll the y cylinder 4, and the construction should be such that even when the plunger is in its raised position, as shown in the drawings, sufficient water will remain in the vessel 30 to cover the Aapertures 32, in order to prevent the escape of compressed air into the cylinder. As a further means for preventing any leakage ofthe compressed air I place a body of water, such as 2, in the bottom of the standpipe, said water covering the opening which leads from the pump, and this acting as a y water seal to resist the tendency of the air to leak. The pipe 22, leading from the damper to the stand-pipe, may be provided with any suitable valve 25 having a handle 2b', which aids in preventing theescape of air by leakage. The stand-pipe is provided above the body of water 2 with a try-cock, as 27, by means lower side of the plunger, and such increased of which any water that accumulates in the stand-pipe may bedrawn off, and I may also use the said try-cock to reduce the air-preslsure inl the pipe, if necessary.,

downward course being opposed by the re- The piston-rod 7 is ordinarily made of such a size that the weight of the piston offsets the l loss of area on the top side of the piston, so g that any given pressure on one side of said @piston is `balanced by an equal pressure on the other side. pipe 18 .will condense, so that the upper side of the piston is acted upon by the condensed :watery which of course has -boiler-pressure. l Inasmuch as the lower side of the piston has acting against it a body ofl water which is lnormally at the same pressure as the condensed steam in the pipe 18, it will be seen that both sides of the piston are subjected to fthe action of `the water under pressure, and

In practice the steam in the as the pressure is the same normally there is a very slight tendency of the water to leak by the piston. Said tendency is counteracted l whenever the piston is at either limit of its 'stroke by the special form of piston, said piston having at each end a flange which abut-s against the cylinderhead, thereby forming a seat which will practically stop. any leakage due to excessive differences in pressure on the two sides of the piston.

The action of my damper-regulator is exceedingly even and steady, this steady nmotion being due to the interposition of the resistance medium between the source of constant pressure and the plunger.

The invention is not limited to the precise construction hereinbefore set forth, for it may be considerably modified within the scope of the appended claims.

Having fully described my invention, what l claim, and desire to secure by Letters Patent, is-

1. In a damper-regulator, a cylinder, a pis- IOO IIO

ton within the cylinder, said piston being connected to the damper, means connecting one end of the cylinder to the boiler whereby one side of the piston is constantly subjected to boiler-pressure, a resistance medium acting on the opposite side of the piston, means to maintain an approximately constant pressure on the resistance medium and means for retarding the motion of the resistance medium.

2. In a damper-regulator, a casing, a plunger Within the casing, means connecting the plunger with the damper, a pipe connecting one end of the casing with the boiler whereby the boiler-pressure acting on one side of the plunger will tend to close the damper, a resistance medium acting on the other side of the plunger, means to maintain an approximately constant pressure on the resistance medium andmeans to retard the motion of said resistance medium.

3. In a damper-regulator, a casing, a plunger within the casing, means connecting the plunger with the damper, means connecting the casing with the boiler whereby the boilerpressure acting on one side of the plunger tends to close the damper, a resistance medium opposing the action of the plunger in closing the damper, means to maintain an approximately constant pressure on the resistance medium, and means to retard the motion of said resistance medium.

4. In an apparatus of the class described, a plunger and its casing, a pipe connected to one end of the casing and communicating with a source of variable pressure, a liquidcontaining vessel, a comparatively small conduit connecting the other end of the casing with said liquid-containing Vessel, and means to maintain an approximately uniform pressure on the liquid in said vessel.

5. In a damper-regulator, a plunger and its casing, a pipe leading into one end of the casing and connected with the boiler, an opentopped liquid-containing vessel, a comparatively1 small conduit from the other end of the casing to the liquid-containing vessel and means for maintaining an approximately constant pressure on the liquid in the vessel.

6. In an apparatus of the class described, a plunger and its casing, a pipe connecting one end of the casing with the boiler, an opentopped liquid-containing vessel, a comparatively small conduit extending from the other end of the casing through the open top of the said vessel and nearly to the bottom thereof, and means for maintaining an approximately constant pressure on the liquid in the Vessel, in combination with a pipe havinga damper operatively connected with the plunger.

7. In an apparatus of the class described, a plunger and its casing, a stand-pipe supporting the casing, a liquid-con taining vessel supported in said stand-pipe and communicating therewith, a relatively small conduit connecting one end ofthe casing with the liquidcontaining vessel, means to maintain an approximately constant air pressure in the stand-pipe, and a pipe connecting the other end of the casing with the boiler, said plunger being adapted to connect with and operate a damper.

8. In a damper-regulator, a plunger and its casing, a pipe connected to one end ot' the casing and communicating with the boiler, a liquid-containing vessel, a conduit connecting the other end of said casing with the liquidcontaining vessel, and means to maintain an approximately constant pressure on the liquid in the vessel, said plunger at each end of its stroke contacting with the ends of the casing outside of the apertures therein. I

In testimony whereof I have signed 4my name to this specification in the presence of two subscribing Witnesses.

THOMAS F. MAHER.

Witnesses p HEATH SUTHERLAND,

LOUISE ROTHSTEIN. 

